With the development of communication technologies, in particular, wireless communication technologies along with the advancement of the electronic industry, a variety of portable terminals that enable voice and data communication anywhere, anytime and with anyone have been developed and generalized. Further, in order to improve the portability of portable terminals, various technologies for miniaturizing the portable terminals (for example, the development of high-density integrated circuit elements, a miniaturization method of an electronic circuit board, etc.) have been developed. As the purposes to use the portable terminals are diversified, terminals that perform various functions, such as a terminal for navigation or a terminal for Internet, have been developed.
Meanwhile, one of the important technologies in wireless communication technology is a technology pertinent to the antenna. Antennas using various methods, such as a coaxial antenna, a road antenna, a loop antenna, a beam antenna, and a super gain antenna, have now been known.
The antennas are for using a specific frequency band. If it is sought to employ various services using different frequency bands, such as voice, data communication and Internet, through portable terminals, a user felt inconvenient with the use of different portable terminals per on a service basis.
To solve this inconvenience, there is a need for the development of a technology where different frequency bands can be used using a single antenna.
In particular, in order to obtain the broadband radiation characteristic, the size (length, etc.) of the antenna must be increased. Such an increase in the size of the antenna becomes an obstacle to not only the miniaturization of the antenna, but also the miniaturization of a portable terminal on which a corresponding antenna is mounted.
Accordingly, there is a need to develop an antenna that can be miniaturized with the broadband characteristic.